Bringing home the bodies of the victims of the Algerian terror siege is Britain’s top priority but it might take some time, David Cameron said today.

The Prime Minister confirmed to MPs that three British nationals were known to have been killed in the attack on the In Amenas gas field and a further three were believed to be dead, along with a Colombian who lived in the UK.

Mr Cameron said his deepest condolences were with the families of the victims and told the Commons work to clear the site of potential traps was continuing.

He said: “Now our most vital work is bringing home those who died. An international team of British, American and Norwegian experts is in close co-operation with the Algerian ministry of justice undertaking the task of formally identifying their bodies.

“We want this process to happen as swiftly as possible but it will involve some intensive forensic and policing work and so may take some time.”

Mr Cameron told MPs it was “important to put on record'' the scale of what happened at the gas field, which is near the Libyan border.

He added: “There is still some uncertainty around the precise facts, but we believe that in total there were some 800 employees working at the In Amenas site at the time of the attack, about 135 of whom were foreign nationals.

“At least 12 were killed with at least a further 20 unaccounted for and feared dead.